This disclosure relates broadly to wind operated musical instruments and particularly to those musical instrument that are resonant in response to vibrating air columns induced therein to produce and amplify the sound waves, resulting in various musical notes.
A horn produces sound through the movement of an enclosed column of air, which is typically produced by the breath of the horn player. For instance, hollow animal horns and conical conch shells were among the earliest varieties of horn. Moreover, horns have been used in purely musical contexts for hundreds of years. Almost any length of tube can serve as a horn of sorts. In this regard, all horns have two common features. A horn has a fundamental pitch frequency (Ff) and can play the members of that fundamental pitch's family of pitch frequencies (n×Ff). For instance, the common bugle has a single fixed length and is, therefore, capable of resonating only at frequencies within a single harmonic series. Thus, the bugle cannot produce a complete major, minor or chromatic scale by itself.
Many approaches have been attempted and implemented to provide a full scale of musical notes. One solution was to have seven ‘bugles’, each, longer (or shorter) than the previous bugle. Each bugle has a half tone pitch frequency separation from the previous bugles' note of the chromatic scale. However, in use, the performer plays each bugle on its' turn, as the musical composition may require.
Another solution provided seven crooks of tubing each longer (or shorter) than the previous. The crooks are inserted in the horn's circuit of air column, to permit a full chromatic scale. However, this approach is often impractical, especially for fast tempo performances, due to the time required to pull one crook and substitute another.
In order to produce more complete scales, most wind instruments are provided with mechanisms to change the effective air column length. Such mechanisms usually comprise telescoping slides, open-able ports, depressible piston keys or rotary valves that provide openings to differing length combinations of tubing sections. Because of the ability to change the effective air column lengths, the instruments can be used to produce many families of harmonic series required to produce scales. The usefulness of the instrument depends of course upon the proficiency, dexterity, and instant recall memory of the player.